### Interface

# GObject TypePlugin

#### Description [src]

    interface GObject.TypePlugin : GObject.Object

An interface that handles the lifecycle of dynamically loaded types.

The GObject type system supports dynamic loading of types. It goes as follows:

1. The type is initially introduced (usually upon loading the module the first time, or by your main application that knows what modules introduces what types), like this: `c new_type_id = g_type_register_dynamic (parent_type_id, "TypeName", new_type_plugin, type_flags);` where `new_type_plugin` is an implementation of the `GTypePlugin` interface.

2. The type’s implementation is referenced, e.g. through `g_type_class_ref()` or through `g_type_create_instance()` (this is being called by `g_object_new()`) or through one of the above done on a type derived from `new_type_id`.

3. This causes the type system to load the type’s implementation by calling `g_type_plugin_use()` and `g_type_plugin_complete_type_info()` on `new_type_plugin`.

4. At some point the type’s implementation isn’t required anymore, e.g. after `g_type_class_unref()` or `g_type_free_instance()` (called when the reference count of an instance drops to zero).

5. This causes the type system to throw away the information retrieved from `g_type_plugin_complete_type_info()` and then it calls `g_type_plugin_unuse()` on `new_type_plugin`.

6. Things may repeat from the second step.

So basically, you need to implement a `GTypePlugin` type that carries a use_count, once use_count goes from zero to one, you need to load the implementation to successfully handle the upcoming `g_type_plugin_complete_type_info()` call. Later, maybe after succeeding use/unuse calls, once use_count drops to zero, you can unload the implementation again. The type system makes sure to call `g_type_plugin_use()` and `g_type_plugin_complete_type_info()` again when the type is needed again.

`GTypeModule` is an implementation of `GTypePlugin` that already implements most of this except for the actual module loading and unloading. It even handles multiple registered types per module.

#### Prerequisite

In order to implement TypePlugin, your type must inherit from`GObject`.

#### Implementations

- GTypeModule

#### Instance methods

###### g_type_plugin_complete_interface_info

Calls the `complete_interface_info` function from the `GTypePluginClass` of `plugin`. There should be no need to use this function outside of the GObject type system itself.

###### g_type_plugin_complete_type_info

Calls the `complete_type_info` function from the `GTypePluginClass` of `plugin`. There should be no need to use this function outside of the GObject type system itself.

###### g_type_plugin_unuse

Calls the `unuse_plugin` function from the `GTypePluginClass` of `plugin`. There should be no need to use this function outside of the GObject type system itself.

###### g_type_plugin_use

Calls the `use_plugin` function from the `GTypePluginClass` of `plugin`. There should be no need to use this function outside of the GObject type system itself.